Detection of a large-scale structure of intracluster globular clusters in the Virgo cluster

Abstract : Globular clusters are usually found in galaxies, and they are an excellent tracer of dark matter. Long ago, it was suggested that there may exist intracluster globular clusters (IGCs) bound to a galaxy cluster rather than to any single galaxy. Here, we present a map showing the large-scale distribution of globular clusters over the entire Virgo cluster. It shows that IGCs are found out to 5 million light years from the Virgo center and that they are concentrated in several substructures much larger than galaxies. These objects might have been mostly stripped off from low-mass dwarf galaxies.